Function TestBucket_Delete_FreelistOverflow

bucket_test.go:376–436

Deleting a very large list of keys will cause the freelist to use overflow.

(t *testing.T)

// Deleting a very large list of keys will cause the freelist to use overflow.
func TestBucket_Delete_FreelistOverflow(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping test in short mode.")
	}

	db := btesting.MustCreateDB(t)

	k := make([]byte, 16)
	// The bigger the pages - the more values we need to write.
	for i := uint64(0); i < 2*uint64(db.Info().PageSize); i++ {
		if err := db.Update(func(tx *bolt.Tx) error {
			b, err := tx.CreateBucketIfNotExists([]byte("0"))
			if err != nil {
				t.Fatalf("bucket error: %s", err)
			}

			for j := uint64(0); j < 1000; j++ {
				binary.BigEndian.PutUint64(k[:8], i)
				binary.BigEndian.PutUint64(k[8:], j)
				if err := b.Put(k, nil); err != nil {
					t.Fatalf("put error: %s", err)
				}
			}

			return nil
		}); err != nil {
			t.Fatal(err)
		}
	}

	// Delete all of them in one large transaction
	if err := db.Update(func(tx *bolt.Tx) error {
		b := tx.Bucket([]byte("0"))
		c := b.Cursor()
		for k, _ := c.First(); k != nil; k, _ = c.Next() {
			if err := c.Delete(); err != nil {
				t.Fatal(err)
			}
		}
		return nil
	}); err != nil {
		t.Fatal(err)
	}

	// Check more than an overflow's worth of pages are freed.
	stats := db.Stats()
	freePages := stats.FreePageN + stats.PendingPageN
	if freePages <= 0xFFFF {
		t.Fatalf("expected more than 0xFFFF free pages, got %v", freePages)
	}

	// Free page count should be preserved on reopen.
	db.MustClose()
	db.MustReopen()
	if reopenFreePages := db.Stats().FreePageN; freePages != reopenFreePages {
		t.Fatalf("expected %d free pages, got %+v", freePages, db.Stats())
	}
	if reopenPendingPages := db.Stats().PendingPageN; reopenPendingPages != 0 {